Disposable surgical drape

ABSTRACT

A disposable surgical drape comprising a folding funnel, folding frame means, and splash shield functions as a fluid collector for use during surgery. A portion of the splash shield is placed under the patient while the remainder extends over the operating table end to direct fluid flow to a folding funnel which is shaped and positioned as desired with folding frame means. Fluid draining into the funnel is collected for measurement. Folding frame means impart a substantially frusto-conical or frusto-pyramidal shape to the funnel in use and employ one or more hinged struts to help maintain the funnel mouth substantially open and horizontal.

This application is a continuation of U.S. patent application Ser. No.08/617,352, filed on Mar. 18, 1996, now U.S. Pat. No. 5,620,010,entitled DISPOSABLE SURGICAL DRAPE which is a continuation-in-part ofapplication Ser. No. 08/109,121, filed 19 Aug. 1993, now U.S. Pat. No.5,395,354.

BACKGROUND

1. Field of the Invention

The invention relates to surgical drapes for maintenance of a surgicalfield and for collection of waste fluid.

2. Waste Fluid in Surgery

Irrigation fluid is commonly used in open surgery as well as inendoscopic examination and surgery performed on the vagina and uterus(transvaginally) and on the urethra and bladder (transurethrally). Anysuch anatomic approach requires sufficient dilation or spreading of thetissues to allow manipulation of the surgical instruments and to givethe surgeon visibility to properly perform the surgery. In ananesthetized patient, clamps and/or retractors are used to maintain opensurgical access and a weighted speculum is commonly employed to maintainthe desired degree of vaginal dilation. A urethra is typicallyprogressively dilated just prior to insertion of an endoscope guidetube.

Waste irrigation fluid drains at least intermittently from open surgicalsites, as well as through and around the endoscope during transvaginaland transurethral endoscopic surgery. An intermittent or continuous flowof water-based (generally nonconducting) irrigation fluid from anexternal reservoir is directed to the surgical site by tubing, syringes,small containers or through the endoscope. Waste irrigation fluiddrains, in turn, from the open surgical access, the vagina or theurethra.

Irrigation fluid flow in the area of surgery removes small pieces ofexcised tissue and blood, continually clearing the surgeon's view of theoperative site(s). Most of the irrigation fluid which flows to theoperative site is subsequently flushed out by additional irrigationfluid, but a portion of the entering fluid may be absorbed through thetissue surfaces of the operative site and through parts of the patient'svascular system exposed by the surgery.

During relatively prolonged and/or invasive surgery, sufficient fluidmay be absorbed to substantially adversely alter the patient's serumelectrolyte balance. Because serious electrolyte imbalances may resultin seizures, coma or death of the patient, the surgeon must havesufficient warning of impending fluid overload to take correctiveaction. While this can be accomplished through frequent estimates ofserum electrolyte levels during the surgical procedures, an easier andless expensive method involves estimation of the mount of fluidabsorbed. In turn, this requires accurate estimates of the difference inthe mounts of irrigation fluid administered and waste irrigation fluidlost. If blood loss can be accurately estimated or is clinicallyinsignificant, the irrigation fluid difference can serve as an estimateof absorbed irrigation fluid. Errors in estimating the difference mostoften arise in estimating the mount of irrigation fluid lost becausesuch fluid is typically hard to recover completely.

A fraction of the drained waste irrigation fluid typically falls onsurgical drapes and thence to the operating table or floor, where it iscommonly lost without being measured. Because the volume of this lostfraction of waste fluid is generally unknown, the mount of irrigationfluid absorbed by the patient is difficult to estimate accurately duringthe course of an operation.

SUMMARY OF THE INVENTION

The present invention relates to apparatus for collecting and measuringwaste irrigation fluid drained from a surgical site, including thatdraining from an endoscope, urethra or vagina and otherwise released inconnection with the use of endoscopic instruments for surgery. Accuratemeasurement of waste irrigation fluid volume facilitates estimation ofthe amount of irrigation fluid absorbed by a patient, and the presentinvention comprises surgical drapes and related apparatus to facilitatecollection and measurement of waste irrigation fluid.

A preferred embodiment of a disposable surgical drape of the presentinvention comprises a splash shield, folding funnel and folding framemeans. These components are made to be coupled adhesively in certainpreferred embodiments so that the pieces may be interchanged and/orpurchased separately. The splash shield and folding funnel arepreferably fabricated substantially of sheet plastic and/or non-wovensheet material which has been treated for water resistance.

The splash shield may be substantially flat or it may have edgesgathered substantially in the manner of a fitted sheet. It is intendedfor substantially horizontal placement under a patient to direct wasteirrigation fluid flow to the folding funnel. Typically, the splashshield will be placed under a patient in the lithotomy position andextend substantially to or over the end of the operating table facingthe surgeon. The splash shield is preferably wide enough to catchsubstantially all waste irrigation fluid draining from the patient whichdoes not fall directly into the funnel portion.

Waste fluid falling on the splash shield when it is substantiallyhorizontal will tend to flow toward the center line of the operatingtable due to the weight of the patient which compresses the table padstogether with the splash shield portion which lies between the patientand the table pads. Waste fluid on the splash shield will further tendto flow toward the end of the operating table facing the surgeon ortoward the other end of the table, depending on how the table is tilted.That which flows toward the surgeon tends to flow over at least aportion of the folding frame means and into the funnel. For this reason,a drip shield which loosely falls over the upper portion of the foldingframe base may optionally be sealingly coupled to the splash shield tofacilitate fluid flow over the folding frame means. The drip shield ispreferably coupled to the splash shield by heat sealing or an analogousprocess which produces a highly water-resistant bond. When so used, thedrip shield will tend to shield from water damage or leakage the(preferably adhesive) coupling of the folding frame means to the foldingfunnel, as well as the (preferably adhesive) coupling of the foldingfunnel mouth to the splash shield.

A folding funnel receives fluid flow from the splash shield, the foldingfunnel comprising a funnel body having a funnel mouth and a funnel mouthedge. At least a potion of the funnel mouth edge is sealingly coupled tothe splash shield (as, for example, by heat sealing of sheet plastic or,preferably, by use of water-resistant adhesives). The folding funnel isso constructed as to have a substantially frusto-conical orfrusto-pyramidal shape when suspended freely under the influence ofgravity with the plane of the funnel mouth uppermost and substantiallyhorizontal. A sufficient length of funnel mouth edge is sealinglycoupled to the splash shield to ensure that substantially all fluid flowover the end of the operating table facing the surgeon will enter thefolding funnel, assuming the funnel mouth is being held substantiallyopen by the folding frame means.

Folding frame means are coupled to the folding funnel for the purpose ofholding open the funnel mouth. Folding frame means comprise asubstantially planar (preferably plastic) base which is relatively rigidcompared to the sheet material of the splash shield and folding funnel.The base has a first end, a second end, a substantially centeredlongitudinal axis extending between the first and second ends, and alongitudinal bending compliance along the longitudinal axis.Additionally, folding frame means comprise at least one resilientelongated strut, each strut having a proximal end and a distal end and alongitudinal bending compliance greater than the base longitudinalbending compliance, each strut proximal end being coupled to the base.Each strut distal end comprises edge coupling means for coupling thestrut to a funnel mouth edge, and hinge means are used for coupling eachstrut to the base. Hinge means may include, for example, a thinnedsection of relatively thicker plastic material (a living hinge) or ahinge of conventional design (analogous to a piano hinge). To maintainthe folding funnel in a preferred orientation during use, strut hingemeans may preferably be designed to transmit torque in a substantiallyvertical plane.

Edge coupling means may comprise, for example, a protrusion of reducedcross-sectional area (relative to the strut) which projects from thedistal end of the strut to engage a hole in the funnel mouth edge.Alternatively, edge coupling means may comprise an adhesive area on thedistal strut end to bond with a portion of the funnel mouth edge. Stillanother alternative edge coupling means may comprise a hook-and-looparea on the distal strut end (covered, for example, with Velcro) toadjustably attach to a corresponding portion of the funnel mouth edgehaving a mating hook-and-loop area.

Struts are intended to fold compactly against the base for shipment andstorage and to hold the funnel mouth open during use of the disposablesurgical drape, preferably so that the funnel mouth edge is in tensionsufficient to keep it from sagging noticeably. Ideally, struts would besubstantially straight while maintaining the desired edge tension, butto allow for manufacturing tolerances in the funnel edge length, strutswill preferably experience more or less longitudinal bending under acompressive load caused by the edge tension. Such longitudinal bendingwill result in a shortened straight-line distance between proximal anddistal ends of a strut (effectively, "strut shortening") relative to thestrut length when straight. The degree of bending compliance is thenconveniently measured in units of strut shortening per unit ofcompressive load. Slightly undersized funnel mouths will resulting inrelatively greater compressive loads and thus more strut shortening,while slightly oversized mouths will result in relatively smallercompressive loads and thus less strut shortening.

Preferred embodiments of the folding frame means comprise from one tothree struts including, for example, first and second resilientelongated struts having lengths and longitudinal bending compliancesthat are substantially equal. A third resilient elongated strut may beadded having a longitudinal bending compliance greater than the firststrut longitudinal bending compliance and length greater than the firststrut length to attain certain desired funnel mouth shapes.

Note that certain preferred embodiments of the invention may also (oralternatively) incorporate a predetermined compliance in tension (unitsof elongation per unit of tension load) in the funnel mouth edge.Further, the funnel mouth edge may be designed to have a non-uniformcompliance in tension when it is desirable to maintain certain portionsof the funnel mouth opening as having a highly repeatable appearance,notwithstanding the effects manufacturing tolerances on strut length andfunnel mouth edge length. Non-uniform compliance in tension ispreferably achieved, for example, by coupling (as by heat sealing)elongated resilient tension members such as plastic or rubber strips toone or more predetermined portions of the funnel mouth edge.

Folding frame means may optionally additionally comprise alongitudinally hinged portion of the base to which all elongated strutsare coupled for adjusting elevation of each strut. The (preferablyliving) hinge is preferably located along at least a portion of thesuperior edge of the hinged portion. When, for example, struts extendsubstantially perpendicularly from a longitudinally hinged portion of abase, adjustment of strut elevation can bring each strut into asubstantially horizontal position. Since in use, struts will normally Hesubstantially in the plane of the funnel mouth, the funnel mouth can bemade substantially horizontal (its preferred orientation in use). Tokeep the funnel mouth substantially horizontal, an elongated hinge lock(preferably in the form of a rod or bar) maintains the adjustment of thelongitudinally hinged portion when it is present by either preventing itfrom closing (that is, moving toward a substantially coplanar positionwith the remainder of the base), or preventing it from opening. In theformer case, the elongated hinge lock is adjustably coupled to the basein such a position as to keep the hinged portion of the base from beingcompletely closed. Such hinge lock coupling to the base can convenientlybe achieved through hook-and-loop areas of the hinge lock ends andcorresponding portions of the base in contact with the hinge lock ends.

In use with the funnel mouth substantially horizontal as describedabove, the funnel weight acts through the strut(s) to create a bendingmoment tending to rotate the base around an axis substantially parallelto its longitudinal axis (thus distorting the splash shield to which thebase is coupled). To resist such a bending moment, the folding framemeans base may comprise at least one stiffener to aid in maintaining adesired elevation of each resilient strut. Stiffeners are (preferablysubstantially coplanar) projections from the base that may be coupled tothe splash shield in the same manner as the base or may simply restagainst it if the applied bending moment will tend to move the stiffenertoward the splash shield. By increasing the degree of rotationalcoupling of the base to the splash shield, the latter structure mayexert greater compensating torque on the base which will tend to holdthe funnel mouth substantially horizontal.

Another structure which may be used (alone or in conjunction with theabove stiffeners) to counteract the above base bending moment insurgical drapes of the present invention comprises at least oneelongated suspension strap adjustably coupling the splash shield and thefolding frame means for holding the open funnel mouth substantiallyhorizontal. Adjustability of the coupling may be attained through useof, for example, hook-and-loop fasteners (such as Velcro) or adhesivepads on one or both suspension strap ends and/or the splash shield.Suspension straps, of course, are preferably adjustably coupled tostruts and may conveniently be adhered to or looped around them, thelatter providing a sliding adjustment. When this loop-adjustmentembodiment is preferred, struts and/or the suspension straps whichadjustably slide over and support them may incorporate relativelyhigh-friction surfaces to provide a relatively stable (but easilychanged) adjustment after the strap is placed in tension due to the loadimposed by holding the funnel mouth substantially horizontal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a preferred embodiment of the foldingframe means comprising optional stiffeners.

FIGS. 2A-C schematically illustrate plan views of various representativefunnel mouth configurations achievable in disposable surgical drapes ofthe present invention.

FIG. 3 schematically illustrates a disposable surgical drape preparedfor use and incorporating optional suspension straps.

DETAILED DESCRIPTION

Disposable surgical drapes of the present invention comprise a splashshield 49, folding funnel 60 and folding frame means 10. The splashshield 49 is for substantially horizontal placement in use as shown inFIG. 3, and the folding funnel 60 is for substantially verticalplacement in use (also shown in FIG. 3). While optionally being soldand/or shipped separately, the folding funnel 60 in use is sealingly(preferably adhesively) coupled to the splash shield 49, with thefolding frame means 10 sealingly (preferably adhesively) coupled to thefolding funnel 60. Note that the folding frame means may optionally beplaced so as to be directly in contact with (and coupled to) the foldingfunnel 60 only or both the folding funnel 60 and the splash shield 49.

The folding funnel 60 comprises a funnel body 50 having a funnel mouth55,55',55" which is a substantially planar area enclosed by a funnelmouth edge 53. Note that through various arrangements of struts 28,28'in relation to the base 20 of folding frame means 10, funnel mouth55,55',55" can be given various shapes (three examples of such shapesbeing schematically illustrated in FIGS. 2A-C). The above surgical drapemay optionally additionally comprise a drip shield 61 sealingly coupledto splash shield 49 to facilitate fluid flow over the base 20 of foldingframe means 10. Other optional components of the above surgical drapeare funnel drain connector 51 (which couples funnel body 50 with funneldrain hose 52) and elongated suspension straps 70 (FIG. 3) foradjustably coupling splash shield 49 and folding frame means 10 forholding funnel mouth 55,55'55" substantially horizontal in use. Notethat suspension straps 70 are preferably coupled to splash shield 49through coupling areas 71 (which may comprise, for example, adhesiveportions or hook-and-eye portions for coupling with correspondingportions on splash shield 49). At the ends of suspension straps 70opposite coupling areas 71, the straps will preferably be coupled tostruts 28,28' as desired in an analogous manner or by looping straps 70around struts 28,28' and coupling the strap ends to the straps 70themselves in the manner described above.

Folding frame means 10 as schematically illustrated in FIG. 1 comprisesa base 20 and two resilient elongated struts 28. Each strut 28 distalend comprises edge coupling means 31 for coupling the strut 28 to afunnel mouth edge 53. Hinge means 14,14' comprise a proximal portion24,24' which is coupled (as by plastic welding or gluing) to base 20 andincludes joint 16,16'. Joint 16,16' may comprise, for example, a thinnedsection of relatively thicker plastic material (a living hinge joint) ora hinge joint of conventional design (analogous to a piano hinge joint).Note that the living hinge joints 16 schematically illustrated in FIG. 1are designed to transmit torque in a substantially vertical plane (thatis, in use they resist the tendency of any weight applied to struts 28(such as a folding funnel 60) to pull the struts 28 below a horizontalplane.

Another feature of the present invention which can be used to keepstruts 28,28' in a substantially horizontal plane is the longitudinallyhinged portion 21 of base 20. FIG. 1 schematically illustrates thesuperiorly located hinge 22 as well as elongated hinge lock 25 formaintaining adjustment of longitudinally hinged portion 21. Elongatedhinge lock 25 is shown as being adjustably coupled (through areasadjacent its ends) to corresponding coupling areas 26 of base 20. Otherfeatures of the present invention which can be used to keep struts28,28' in a substantially horizontal plane are the stiffeners 30 (alsoshown in FIG. 1). Note that when a third resilient elongated strut 28'is placed between two relatively shorter struts 28 as schematicallyillustrated in FIG. 2C, the funnel mouth 55" which is created isrelatively deeper than the corresponding funnel mouth 55 which iscreated by two struts 28 (schematically illustrated in FIG. 2A). Thedeeper funnel mouth 55" will tend to exert a greater bending moment onbase 20 than funnel mouth 55. To resist a greater bending moment, eachstrut may preferably have an "I" beam or "H" beam cross-section toresist bending along its longitudinal axis in a substantially verticalplane under the weight of the funnel (i.e., relatively low verticalbending compliance), while at the same time having a substantiallygreater longitudinal bending compliance in a substantially horizontalplane (i.e., relatively high horizontal bending compliance).

Edge coupling means 31 (shown in FIG. 1) are intended to reversiblyprevent lateral movement of the distal end of a strut 28,28' withrespect to a portion of the funnel mouth edge 53. Edge coupling means 31may comprise a small protrusion at the distal end of a strut 28 (asschematically illustrated), the protrusion being sized to allow itsinsertion into a properly located and closely fitting hole in the funnelmouth edge 53. Edge coupling means may also comprise a socket portionmolded into or otherwise coupled to the funnel mouth edge, the socketportion reversibly coupling preferably with a snap or friction fit) aball portion located at a strut 28,28' distal end. Still anotherembodiment of edge coupling means 31 may comprise a separate socketportion which can be reversibly applied to a ball portion on a strut 28distal end with a portion of the funnel mouth edge 53 reversibly trappedbetween the ball portion and the socket portion. The latter edgecoupling means 31 embodiment is intended to be adjustably applicable toany of a plurality of locations on the funnel mouth edge 53. Note thatthe ball and socket need not be spherical or smooth, but may besubstantially ellipsoidal or substantially cylindrical or may compriseone or more solid angles to enhance its anchoring function and/or itsreversible coupling function.

In general, a strut 28,28' substantially crosses from one portion of thefunnel mouth 55,55',55" to another portion. The funnel mouth 55,55',55"is preferably maintained open in some desired shape and in tension bythe combined resilience of the base 20 and one or more struts 28,28'.While longitudinal (that is, bending) compliance of both the base 20 andstruts 28,28' contributes to shaping of the funnel mouth, strutlongitudinal compliance exceeds base longitudinal compliance inpreferred embodiments. Note also that certain portions of the funnelmouth edge 53 may preferably have greater compliance in tension thanadjacent portions, the non-uniform compliance in tension being useful incompensating for manufacturing tolerances in various portions of thedisposable surgical drape while assuring a substantially repeatable andpredetermined funnel mouth shape.

The present invention is particularly adapted for use with a malleablespeculum during transvaginal endoscopic surgery. A malleable speculummay be used independently or may be sealingly coupled either reversiblyor substantially irreversibly to an apron-funnel-splash shield assemblyto facilitate collection of waste fluid drainage (see U.S. Pat. No.5,395,354, Mar. 7, 1995, Vancaillie, a divisional of application Ser.No. 08/109,121, filed 19 Aug. 1993, incorporated herein by reference).The malleable speculum may be used without the apron-funnel-splashshield assembly for operations wherein accurate estimation of theamounts of drained and absorbed irrigation fluid is regarded asunnecessary because the absorption of clinically significant amounts isunlikely. However, because the duration and/or invasive character of asurgical procedure may be difficult to precisely predict, a requirementfor collection and accurate measurement of drainage fluid is oftenpresumed. Thus, the malleable speculum may be present in a preferredembodiment of the present invention as part of a drape assemblycomprising a speculum, an apron, a folding funnel, a splash shield, andfolding frame means. This assembly acts to provide the desired degree ofvaginal dilation and to improve the accuracy of fluid absorptionestimates during endoscopic surgery. The latter function includescollecting and measuring both the irrigation fluid which falls directlyon components of the drape assembly and that which reaches the drapeassembly after flowing over the patient or portions of the surgical andoperating room support apparatus associated with the operation.

What is claimed is:
 1. A disposable surgical drape, comprisinga splashshield for substantially horizontal placement to direct fluid flow to afolding funnel; a folding funnel for receiving fluid flow from saidsplash shield, said folding funnel comprising a funnel body having afunnel mouth and a funnel mouth edge, at least a portion of said funnelmouth edge being sealingly coupled to said splash shield; and foldingframe means coupled to said folding funnel for holding open said funnelmouth, wherein said folding frame means further comprises a base havinga first end, a second end, a substantially centered longitudinal axisextending between said first and second ends, and a longitudinal bendingcompliance along said longitudinal axis; at least one resilientelongated strut, each said strut having a proximal end and a distal endand a longitudinal bending compliance greater than said baselongitudinal bending compliance, each said strut proximal end beingcoupled to said base, wherein, each said strut distal end comprises edgecoupling means for coupling said strut to a funnel mouth edge; and hingemeans for coupling each said strut to said base.
 2. The surgical drapeof claim 1 additionally comprising a drip shield sealingly coupled tosaid splash shield to facilitate fluid flow over said folding framemeans.
 3. The surgical drape of claim 1 additionally comprising at leastone elongated suspension strap adjustably coupling said splash shieldand said folding frame means for holding said open funnel mouthsubstantially horizontal.
 4. The disposable surgical drape of claim 1,wherein said folding funnel mouth edge has a non-uniform compliance intension.